The present invention relates to a data exchanging system for transmitting data by optical coupling between electrical devices, and more particularly, to a system for transmitting data between a portable bar code reader and a plurality of remote vending machines.
Generally, data exchange between electrical equipment is performed by electric coupling. This coupling is classified into two types, such as, direct current (D.C.) coupling and alternating current (A.C.) coupling. D.C. coupling can be supplied at low cost, and hence, low price. However, D.C. coupling is easily influenced by electrical noise. A.C. coupling can be employed to reduce electrical interference, however, the cost to supply such systems is too high.
Alternatively, optical coupling may be used in a communication system for exchanging data. Optically coupled systems are usually used in equipment because these systems can be provided at low cost and are not affected by electrical interference. However, when data is to be exchanged between a plurality of systems, the format used for data transmission must be considered. This is because data can only be optically transmitted between devices which use the same data format.
As an example, consider a data gathering system for use with automatic vending machines. In such a system, vending machines are placed at many remote locations. Goods are supplied and coins are collected from these machines periodically at suitable intervals. When supplying goods and collecting coins, the person in charge has to gather administrative data such as the number of articles sold, total sales, quantities of goods supplied, and so forth. The data gather system allows automatic gathering of a good deal of administrative data simply and quickly, thereby saving labor.
A typical data gather system (for gathering administrative data from a plurality of automatic vending machines includes electric or optical coupling means for communicating with the control section of the vending machine. The control section of the vending machine include memory for storing the information to be transmitted. The data gathering device collects data from the memory of the vending machine via its control section. However, this system suffers from a disadvantage in that the data formats and interface conditions for data transmission differs according to the manufacturer of the vending machine, i.e., they are not standardized. Companies which supply goods to automatic vending machines must deal with machines of different manufacturers and, therefore, are obliged to carry several different data gathering devices satisfying different interface conditions and data formats. Such a system is quite uneconomical and impractical.
Thus, from the view point of utility and price, gathering data from automatic vending machines is preferably conducted by a single commercially available portable data gathering terminal. This, however, is difficult to realize because of diversification of the coupling interfaces.
Furthermore, the data exchanging system is not only used for gathering stored data from the automatic vending machine, but is also used to provide vending machine operating input data to the automatic vending machines. For instance, in vending machines for brewing coffee, the amount of coffee bean, cream, sugar, and density of brewing coffee must be precisely selected. Therefore, this information should be manually provided to the control device of the coffee vending machine. However, the operation for providing the vending machine with information representing suitable data is complicated and time consuming.